reflect: replace all_test with copy from upstream

src/reflect/internal/example1/example.go

@@ -0,0 +1,10 @@
+// Copyright 2021 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package example1
+
+type MyStruct struct {
+	MyStructs []MyStruct
+	MyStruct  *MyStruct
+}

src/reflect/internal/example2/example.go

@@ -0,0 +1,10 @@
+// Copyright 2021 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package example2
+
+type MyStruct struct {
+	MyStructs []MyStruct
+	MyStruct  *MyStruct
+}